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Fish of The Month

Nyassachromis prostoma

is an open water mouthbrooding cichlid from Lake Malawi.

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Members-only Picnic

mtg mod picnic

Sunday, September 14th at Noon

Our annual members-only picnic at Bruce Canaday's house will feature food and fun for the whole family. Enjoy some BBQ and visit Bruce's, fishroom.
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Rare Fish Auction

Sunday, August 10th | 6PM - ?

GCCA brings in 25-50 bags of rare and hard to find cichlids offered to the highest bidder. GCCA members-only.

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Oreochromis mossambicus

Oreochromis mossambicus

Above Oreochromis mossambicus "red". Photo by Rick Borstein

General

Oreochromis mossambicus, Gold FormSearching for information on this fish on the internet is enlightening. Most references are not aquarium-related, but instead are dire ecological warnings. To put it bluntly, this cichlid is an extremely fecund fish that is invading aquatic habitats from the United States to Australia.

Oreochromis mossambicus does make a fine aquarium fish. It's easy to care for, grows quickly and is interesting to breed. The wild type is a dull greenish fish, but a number of interesting color varieties such as the red (above), orange and gold (see right) are available to liven up your tank.

If you've ever had Tilapia at your favorite seafood restaurant, Oreochromis mossambicus is the fish you ate! Interestingly, many of the color varieties were bred specifically to make them more palatable to consumers! Apparently, an orange fish makes folks think of Red Snapper. Go figure!

Many of the characteristics that make this a good farm fish, make it a terrible nuisance when populations become feral.

Please do not release aquarium specimens in the wild!

Why does Oreochromis mossambicus so easily beat out native fish? Here's why

  • It eats just about anything including algae and detritus thus exploiting a food resource not used by most native fishes. Oreochromis mossambicus will happily switch from vegetable to animal sources. It's not picky!
  • It can live just about anywhere including ponds, reservoirs, drainage ditches, riverine environments, even brackish water.
  • It's tough! Oreochromis mossambicus can tolerate a wide range of water temperatures from 40F to 104F, low oxygen levels, poor water quality and pollution.
  • It's a prolific mouthbrooder! Broods can be in the hundreds and females can carry several broods a year.
  • It will breed even in poor conditions. Even when food is low or nearly unavailable, this fish will continue to breed.
  • It gets big (1.5 lbs and may exceed 15 inches long) but breeds young at only two inches.

So, you can see why the title of one PDF I found on the web was 100 OF THE WORLD’S WORST INVASIVE ALIEN SPECIES.

Habitat

Oreochromis mossambicus is an African cichlid and is found in a variety of areas including Lake Tanganyika and Lake Victoria. In Lake Tanganyika, it tends to populate estuary areas, but is found througout the lake. It is a non-specialized feeder and hasn't adapted to take advantage of many of the rocky habitats containing tenacious algae, thus it hasn't threatened the 'scraper' species such as tropheus, etc.

Care

Oreochromis mossambicus is easy to keep . . . when young. You can abuse it, frankly, and it will survive. That said, it is a messy eater, so frequent water changes are necessary if you want optimal growth.

And grow they will! This is a fast-growing fish.

However, when this fish gets bigger, it can get increasingly aggressive. Who needs a mean foot long cichlid? Actually, I can think of some GCCA members who do, but this fish is not interesting enough to keep at this size for even the most die-hard tank buster fan.

Feeding

This fish will eat anything. Flake, pellets, zucchini, algae wafers . . . you name it! They are greedy, too. They will fill up their buccal cavities (males and females) and carry around any food they can't eat right away.

Not only does Oreochromis mossambicus like to eat, it will do so even under conditions that other fish won't. I once moved a group of several Oreochromis mossambicus to another tank, an operation which would normally stress a fish and have them cowering for a while. Nope, not for this fish! They were eating again inside of 30 seconds!

Breeding

Like most African cichlids, Oreochromis mossambicus is a maternal mouthbrooder. This fish is easy to breed. It's the 'convict' of the mouthbrooder set. It is hard to tell the males from the females, but the fish seem to figure it out on their own.

This fish pretty much breeds itself. Put five to six fish in a forty gallon or larger tank and leave them alone. They will breed at eight to nine months.

Females drop eggs in a nest constructed by the male. Interestingly, in contrast to most Haps, the eggs are fertilized by the male before the female takes them up in her mouth. The eggs are incubated for 3 to 5 days. Young fry remain in the female’s mouth for another ten to fourteen days.

Realizing that I wanted to breed this fish before it got too big, I stripped a young female's second brood shortly after the eggs were laid. This litle two inch fish had over sixty small 3/32" diameter eggs. I placed these eggs in a commercial egg tumbler with some Acriflavine Plus (anti-fungal) at 80F and performed daily 50% water changes replacing the anti-fungal as necessary. Eleven days later I had over 30 babies left which was plenty!

The young fry are able to eat newly hatched baby brine shrimp immediately. After one week, I switched them to crushed flake food and they grew rapidly.

Retail Price

If you can't find this fish at your local pet shop, ask if they will order it for you. After assuring the shopkeeper that you're not crazy, you can expect to pay $3-7 for this fish. It is occasionally available at GCCA meetings, shop hops and auctions where you can buy a whole bucket of these fish for a buck or two. The owner will be only too glad to give them to you.

Oreochromis mossambicus is readily available.

Report April 2002 and updated August 2011 by Rick Borstein.

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